June 16, 2001

Protease Inhibitor Resistant HIV

Might Not Adversely Affect T-Cell Counts

from the ADVOCATE



Researchers from the Gladstone Institute of Virology and Immunology at the University of California, San Francisco, have discovered that HIV that is resistant to protease inhibitors seems less able to infect the thymus, the organ that produces T cells, reports HIVandHepatitis.com.

Patients with protease inhibitor–resistant HIV can conceivably continue to produce new T cells even in the face of high viral loads, they said. “Just because they have high viral loads and drug-resistant virus, it doesn’t necessarily mean that their T-cell counts are going to plummet,” said lead study author Cheryl Stoddart.

Researchers inoculated both wild-type and drug-resistant virus into human thymus cells, which were then implanted into mice. Weeks later, the wild-type virus had substantially depleted the number of healthy thymus cells. The drug-resistant virus replicated much more slowly and barely affected thymus cells—on average, 12 times fewer thymus cells became infected with drug-resistant virus than with wild-type virus.

“The difference in the way the virus grew could not be more extreme,” Stoddart said. The researchers plan additional studies focusing on thymus cells to determine exactly why the drug-resistant virus is less able to infect them.